Improvement in device for changing the speed of machinery



T. C. HARGRAVE. DEVICEl EGE GEANGING TEE SPEED 0Ev MACHINERY.

No. 82,941. Patnted Oct. 13, 1868.

VII..

Tins 00,. PHOTLLLITHO.. wAsnlNToN D c att-a sa THOMAS C. HARGRAVE, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO HIMSELR'WILLIAM B. CHARLTON, AND H. K. MOORE.

Lamm raamt No. 82,941, dated october 13,1868.

mRovEMENT 1N pEvIcE Eon? CHANGING- TEE SPEED or MACHINERY,

The Schedule referred to in these Letters Patent and making pari: of the aime.

To all whom it 'mu/y.

Be it known that I, Tuoi/ms G. HAnenAvE, of Boston, in the county of Suifolk, and State of Massachusetts, have invented an Improved Device for Changing the -Speed of Machinery, of which the fol- .lowing is a full, clear, and exact description, reference being had to the accompanying drawings,makingl part of this specification, in which- Figure l is a plan'ofl my improved' device.

Figure 2 is an end elevation of the same.

Figure 3 is a section on the line a: n: of fig. 1.

Figure 4 is a section on the line y y of iig. 1;

This invention consists in'an arrangement of mechanism by which the speed Aof machinery may be expeditiously lchanged without any cessation of movement, and -without the sudden jerk which is experienced where the ordinary clutch is employed;

To enable others skilled in the art to understand and use my invention, I will proceed to describe the manner in which I have carried itout.

In the said drawings, A represents an ordinary drum or pulley, the shaft, l), of which runs in bearings in the standards c c, and from this drum motion is commimi'- cated-tothe pulleys B C, by meansl of a belt, D, which is shifted from one to the other by a shipper-lever, E, operated by hand or automatically, by means of suit-v able connections.

The manner in which the motion'of thepulleys B and C is communicated to the driving-shaft of the machine will now be described.

The pulley B is permanently secured to the outer end of a hollow shaft, d, which revolves on a stationary shaft, e, projecting out horizontally from a standard, G, rising from the bed v,.H, and to the opposite extremity of the shaft dis secured a gear, I, which engages with a gear, K,of the same diameter, which runs on a short horizontal shaft or stud, j, projecting out from the standard G i Over the hollow shaft d is fitted, so as to revolve freely thereon, another hollow shaft, L, which carries the pulley C, and to the inner extremity of the shaft L is secured a gear, g, which engages with a larger gear, M, secured to the gear K. and revolving there-` with on the stud f.

f These gears KM are placed upon a stationary stud, f, for convenience in lillustrating my invention; but in practice they -are intended to'beboth keyed to the driving-shaft of the" machine to which my improved device for changing speed is applied.

The end. of the shaft L opposite to the gear g bears against a boss or projection, 5, on the inner face of the pulley B, and thus serves to prevent the inner edges ofthe pulleys B and C from coming into ContactA with each other.

When the belt is upon the pulley B, its motion will be communicated through the shaft d to the gear I, which engages with the gear K, and these gears being of equal size, the driving-shaft'of the machine will be revolved at the same speed as the pulley B; but when the belt is shifted on to the pulley C, the motion is communicated through the hollow shaftL to the gear g, which engages'with the gear M; and the gear g, having but about one-half the number cf teeth-of the gear M, the driving-shaft'will be revolved at only onehalf the speed of the pulley C, and consequently the machine is ,driven at only one-halfthe speed when the belt is`on the pulley (l, that it is when the vbelt is on the pulley B, and it will be seen that the several gears are so connected together, that, whether the b'elt is on the pulley B or C, they will both be revolved simultaneously, although at diiierent rates of speed. By changing the relative sizes of the gears, the proportional rate of speed communicated from the pulleyyB or C may be varied as desired, and it is evidentthat if more than two di'erent rates of speed shouldb required, the number of pulleys may be increased, each one having an independent hollow shaft, provided with a gear engaging with another gear on the drivingshaft of the machine. In general, however, only two different rates of speed are required.`

The above-described device for changing the speed of machinery while it is in motion, is simple, compact, and not liable to get out of order, while it may be applied to any description of machinery in 'which it is desirablel to change the rate of speed expeditiously, l,Without any sudden jerk, and without any'cessation of motion.

C' lat'm.

means of which the rateof. speed may be expeditiously A changed, the whole combined-`and arran ged substantially as described.

T. 0,'HARGRAVF.. Witnesses: j

P. E. Tnscnnnncnnn,

N. Wg STEARNS. 

